Surface treatment composition and method for removing Si component and reduced metal salt produced on the aluminum die cast material in etching process

Abstract

A surface treatment composition and method for removing Si and reduced metal salt produced during etching of an aluminum die cast material (“ALDC material”) without generation of nitrogen oxide (NOx) or hydrogen fluoride (HF). In surface treatment of an ALDC material containing Si, Fe, Cu, Mn, Mg, Zn and Ni, the surface treatment composition for removing Si and reduced metal salt from the surface of the ALDC material after etching comprises hydrogen peroxide 300 to 950 g/l, fluorine ion-containing inorganic salt 1 to 300 g/l and balance water. The surface treatment method for removing Si and reduced metal salt from the surface of an ALDC material after etching comprises the step of dipping the ALDC material into the above described surface treatment composition. The aforementioned surface treatment composition effectively removes the Si and reduces metal salt impurities from the surface of the ALDC material without any problems such as NOx or HF gas which is harmful to the human and waste water treatment. Further, residue oil is also removed from the ALDC material.

1. A surface treatment composition for removing Si and reduced metal salt from the surface of an aluminum die casting (ALDC) material after etching without emitting nitrogen oxide (NOx) and/or hydrogen fluoride (HF) gas, the surface treatment composition comprising an effective amount of hydrogen peroxide 300 to 950 g/l, fluorine ion-containing inorganic salt 150 to 300 g/l and water-soluble ether 1 to 30 g/l to remove Si and reduced metal salt from surface treatment of an ALDC material. 
     
     
       2. The surface treatment composition according to  claim 1 , wherein said water-soluble ether is selected from the group consisting of ethylene glycol monobutyl ether, dipropylene glycol monoethyl ether and mixture thereof. 
     
     
       3. The surface treatment composition according to  claim 1 , wherein said hydrogen peroxide is 300 to 700 g/l. 
     
     
       4. The surface treatment composition according to  claim 1 , wherein said fluorine ion-containing inorganic salt is 200 to 300 g/l. 
     
     
       5. The surface treatment composition according to  claim 1 , wherein said fluorine ion-containing inorganic salt is selected from the group consisting of ammonium bifluoride (NH 4 HF 2 ), ammonium fluoride (NH 4  F) and mixture thereof. 
     
     
       6. A surface treatment composition according to  claim 1 , wherein the composition dissolves residual oil from the surface of an aluminum die casting (ALDC) material after etching. 
     
     
       7. A surface treatment composition according to  claim 1 , wherein the composition prevents re-adhesion of the reduced metal salt and Si component to the material surface. 
     
     
       8. A surface treatment composition according to  claim 1 , wherein the reduced metal salt to be removed from the surface of an aluminum die casting (ALDC) material comprises iron, copper, manganese, magnesium, zinc and nickel. 
     
     
       9. A surface treatment method of ALDC material for removing Si and reduced metal salt from the surface of an ALDC material after etching, the method comprising the step of dipping the ALDC material into a surface treatment composition according to  claim 1 . 
     
     
       10. A surface treatment composition for removing Si and reduced metal salt from the surface of an aluminum die casting (ALDC) material after etching without emitting NOx and/or HF gas the surface treatment composition comprising: an effective amount of hydrogen peroxide 300 to 950 g/l, fluorine ion-containing inorganic salt 150 to 300 g/l, water-soluble ether 1 to 30 g/l and balance water to remove Si and reduced metal salt from surface treatment of an ALDC material. 
     
     
       11. The surface treatment composition according to  claim 10 , wherein said water-soluble ether is selected from the group consisting of ethylene glycol monobutyl ether, dipropylene glycol monoethyl ether and mixture thereof. 
     
     
       12. The surface treatment composition according to  claim 10 , wherein said hydrogen peroxide is 300 to 700 g/l. 
     
     
       13. The surface treatment composition according to  claim 10 , wherein said fluorine ion-containing inorganic salt is 200 to 300g/l. 
     
     
       14. The surface treatment composition according to  claim 13 , wherein said fluorine ion-containing inorganic salt is selected from group consisting of ammonium bifluoride (NH 4 HF 2 ), ammonium fluoride (NH 4 F) and mixture thereof. 
     
     
       15. A surface treatment composition according to  claim 10 , wherein the composition dissolves residual oil from the surface of an aluminum die casting (ALDC) material after etching. 
     
     
       16. A surface treatment composition according to  claim 10 , wherein the composition prevents re-adhesion of the reduced metal salt and Si component to the material surface. 
     
     
       17. A surface treatment composition according to  claim 10 , wherein the reduced metal salt to be removed from the surface of an aluminum die casting (ALDC) material comprises iron, copper, manganese, magnesium, zinc and nickel. 
     
     
       18. A surface treatment method of ALDC material for removing Si and reduced metal salt from the surface of an ALDC material after etching, the method comprising the step of dipping the ALDC material into; a surface treatment composition according to  claim 2 .